Using the smartphone's camera, the app reads commercial and research colorimetric tests, and, using a mathematical algorithm, compares the result with stored calibration values. It then delivers the test's result right on the smartphone's screen. The test results can be stored on the smartphone, analyzed for trends, or emailed.

The app could make monitoring conditions such as diabetes, kidney disease, and urinary tract infections much clearer and easier for both patients and doctors. It may eventually be used to slow or limit the spread of pandemics such as HIV, tuberculosis, and malaria in the developing world.

"This is the kind of low cost, lab in your hand we need," Eric Topol, MD, chief academic officer at San Diego-Scripps Health and chief medical advisor to AT&T, said over Twitter.

The Colorimetrix app can substitute for a dedicated test reader. (Courtesy University of Cambridge)

Colorimetrix' website explains that the app can be used with dipsticks and lateral-flow tests as well as colorimetric tests in solution. "The Colorimetrix app was designed to quantify colorimetric tests, providing rapid on-site screening when there is lack of equipment, fast responses are needed, and connectivity is required," the app's developers say.

The Cambridge researchers have published their work in the journal Sensors and Actuators B: Chemical. Their paper is also available online on ScienceDirect. Lead author Ali K. Yetisen, a Cambridge PhD student, wrote in the abstract, "The app transformed the smartphone into a reader to quantify commercial colorimetric urine tests with high accuracy and reproducibility in measuring pH, protein, and glucose. The results showed linear responses in the ranges of 5.0-9.0, 0-100 mg/dL and 0-300 mg/dL, respectively."

The team is planning to conduct clinical testing of the app for kidney function and infections in at Addenbrooke's Hospital (Cambridge, UK).

The result of a collaboration between researchers from the Cambridge Departments of Chemical Engineering & Biotechnology, and Engineering, the app is currently available for Android and iOS for research purposes via the Colorimetrix website.